Microsoft Official: Malware Recovery Not Always Possible
Wednesday, April 05, 2006
By Ryan Naraine
LAKE BUENA VISTA, Fla. — In a rare discussion on the severity of the Windows malware scourge, a Microsoft (MSFT) security official said businesses should consider investing in an automated process to wipe hard drives and reinstall operating systems as a practical way to recover from malware infestation.
"When you are dealing with rootkits and some advanced spyware programs, the only solution is to rebuild from scratch. In some cases, there really is no way to recover without nuking the systems from orbit," Mike Danseglio, program manager in the Security Solutions group at Microsoft, said in a presentation at the InfoSec World conference here.
Offensive rootkits, which are used hide malware programs and maintain an undetectable presence on an infected machine, have become the weapon of choice for virus and spyware writers and, because they often use kernel hooks to avoid detection, Danseglio said IT administrators may never know if all traces of a rootkit have been successfully removed.
He cited a recent instance where an unnamed branch of the U.S. government struggled with malware infestations on more than 2,000 client machines.
"In that case, it was so severe that trying to recover was meaningless. They did not have an automated process to wipe and rebuild the systems, so it became a burden. They had to design a process real fast," Danseglio added.
Danseglio, who delivered two separate presentations at the conference — one on threats and countermeasures to defend against malware infestations in Windows, and the other on the frightening world of Windows rootkits — said anti-virus software is getting better at detecting and removing the latest threats, but for some sophisticated forms of malware, he conceded that the cleanup process is "just way too hard."
"We've seen the self-healing malware that actually detects that you're trying to get rid of it. You remove it, and the next time you look in that directory, it's sitting there. It can simply reinstall itself," he said.
"Detection is difficult, and remediation is often impossible," Danseglio declared. "If it doesn't crash your system or cause your system to freeze, how do you know it's there?
"The answer is you just don't know," he explained. "Lots of times, you never see the infection occur in real time, and you don't see the malware lingering or running in the background."
He recommended using PepiMK Software's SpyBot Search & Destroy, Mark Russinovich's RootkitRevealer and Microsoft's own Windows Defender, all free utilities that help with malware detection and cleanup, and urged CIOs to take a defense-in-depth approach to preventing infestations.
Danseglio said malicious hackers are conducting targeted attacks that are "stealthy and effective" and warned that the for-profit motive is much more serious than even the destructive network worms of the past. "In 2006, the attackers want to pay the rent. They don't want to write a worm that destroys your hardware. They want to assimilate your computers and use them to make money.
"At Microsoft, we are fielding 2,000 attacks per hour. We are a constant target, and you have to assume your Internet-facing service is also a big target," Danseglio said.
Danseglio said the success of social engineering attacks is a sign that the weakest link in malware defense is "human stupidity."
"Social engineering is a very, very effective technique. We have statistics that show significant infection rates for the social engineering malware. Phishing is a major problem because there really is no patch for human stupidity," he said.
The most recent statistics from Microsoft's anti-malware engineering team confirm Danseglio's contention. In February alone, the company's free Malicious Software Removal Tool detected a social engineering worm called Win32/Alcan on more than 250,000 unique machines.
According to Danseglio, user education goes a long way to mitigating the threat from social engineering, but in companies where staff turnover is high, he said a company may never recoup that investment.
"The easy way to deal with this is to think about prevention. Preventing an infection is far easier than cleaning up," he said, urging enterprise administrators to block known bad content using firewalls and proxy filtering and to ensure security software regularly scans for infections.
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